Electrical conductor



No. 463,512. Patented Nov. 17, 1891.

UNTTED STATES PATENT OFFICE.

PHILIP HENRY HOLMES, OF GARDINER, MAINE, ASSIGNOR TO THE HOLMES FIBRE-GRAPHITE MANUFACTURING COMPANY, OF CHICAGO, ILLINOIS.

ELECTRICAL CONDUCTOR.

SPECIFICATION forming part of Letters Patent No. 463,512, dated November 17, 1891.

Application led June 2, 1891. Serial No. 394,887. (No modeLV To a/ZZ whom it may concern,.-

Be it known that I, PHILIP HENRY HoLMEs, of Gardiner, in the county of Kennebec and State of Maine, have invented certain new and useful Improvements in Electrical Conductors; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The object of my invention is to make an electrical conductor-such, for instance, as a pencil for electric-arc lights or a commutatorbrush for dynamos, motors, tbe-that will not be consumed or wear away so quickly as usual. This object I attain in the following manner, reference being had to drawings, in which- Figure l is a side view of an arc-light pencil made in accordance with my invention, and Fig. 2 is a view of one form of commutator-brush.

The arc-light pencil (shown in Fig. 1) is made, essentially, of plumbago, in a finelydivided state, which is molded into the desired form by pressure and then treated with a drying-oil of such character that it will resinify on being dried or subjected to heat.

In order to strengthen the conductor and to hold the plumbago during the manufacture of theV conductor, I mix with the plumbago nely-divided fiber, preferably Wood fiber.4

The proportion of fiber to plumbago may vary according to circumstances, but I prefer to have as much plumbago as possible in the pencil and in large excess of the other ingreclients.

I have obtained very good results from pencils in which the proportion of plumbago to ber vary from four to one to thirty-live to one.

The material for the conductor I prefer to manufacture in the manner set forth in an application tiled by me on January 7,1891, Serial No. 377,028.

I iind that an arc-light pencil made in accordance with my invention lasts considerably longer than a pencil made of the ordinary gascarbon, and will also giveamore satisfactory light.

In making a com1nutator-brush essentially and mainly of plumbago I preferably shape it as shown in Fig.`2, and use a compound of plumbago and fiber bound together by a drythe accompanying ing-oil of resinif yin g character. Such abrush not only constitutes a good electrical conductor, but it also reduces the friction between the brush and commutator. of the brush will not wear away so fast as do the brushes'made of metal or carbon in the usual manner.

Brushes made of my improved material I have used on dynamos and motors with excellent results, the brushes running smoothly, preventing sparking, and otherwise improving the machine.

In making either the arc-light pencil or the commutator-brush I prefer to apply thereto by plating or otherwise a coating of copper or other suitable electrical conducting metal, which not only strengthens the pencil -or brush, but also is a good conductor of electricity.

The material maybe used for electrical contact-points, and in fact for any electrical use to which such a material can be applied.

Having fully described my invention, what yI claim as new, and desire to secure by Let- 1. An electric conducting composition made of compressed plumbago united by a dryingoil as a binder and solidied and hardened, substantially as specified. 2. An electric conducting composition made of finely-divided plumbago and inely-divided ber compressed into a form and united by a binder and solidified and hardened, substantially as specified.

3. A hardened electric conducting composition of plumbago, fiber, and a drying-oil as a binder, substantially as described.

4t. A hardened electric conducting composition, composed of finely-divided plumbago, inelydivided fiber, and a drying-oil as a binder to hold the particles of plumbago in electrical contact with each other, substantially as described.

5. A hardened electric 'conducting composition composed of plumbago, divided ber, and a drying-oil, the plumbago being in excess, substantially as specified.

In testimony whereof I have signed this specication in the presence of two subscribing witnesses.

PHILIP HENRY HOLMES. Witnesses:

A. M. SPEAR, CHARLES L. ANDREWS.

Hence the material IOO 

